According to a conventional electromagnetic relay of this kind, a plurality of contact units are arranged on either side of a partition wall, and an actuating force of an armature of an electromagnet unit is transmitted to the moveable contact pieces of the contact units via an actuating member consisting of an electrically insulating member. Since such an actuating member must not interfere with the partition wall and the fixed contact pieces, the actuating member must be provided with an elongated extension for transmitting the driving force over a certain distance. This distance is required for the partition wall to provide a favorable insulation. Further, the interior of the casing of the relay is provided with a limited space because of the requirement to minimize the external dimensions of the electromagnetic relay. For these reasons, the extension of the actuating member must be elongated.
Hence, some difficulty arises in ensuring the mechanical strength of the actuating piece or its extension. In particular, because the actuating member is exposed to heat generated by arc discharges occurring in switching over the contact points, some care must be taken in order to avoid thermal deformation of the actuating member and its extension.
Further, because such an electromagnetic relay has a very limited internal space, it is difficult to accommodate a guide structure which can guide the movement of the actuating member in a stable fashion.